The present invention relates generally to technique for fracturing a formation to facilitate production of fluid, and particularly to the use of an expandable device deployed within a wellbore to facilitate the fracturing process.
In the conventional construction of wells for the production of fluids, such as petroleum, natural gas and other fluids, a wellbore is drilled in a geological formation to a reservoir of the desired production fluids. In some formations, flow of the desired production fluid to the wellbore is inhibited by, for example, the structure and composition of the formation. In these situations, fracturing can be used to stimulate the production of fluid from the subterranean formation.
One type of fracturing is referred to as hydraulic fracturing in which a fracturing fluid is injected through a wellbore and against the face of the formation at a pressure and flow rate sufficient to overcome the minimum principal stress in the reservoir and thus propagate fractures in the formation. The fracturing fluid typically comprises a proppant, such as 20-40 mesh sand, bauxite, glass beads, etc., suspended in the hydraulic fracturing fluid. The fluid and proppant are transported into the formation fractures and function to prevent the formation from closing upon release of the pressure. The proppant effectively fills fractures to provide permeable channels through which the formation fluids can flow to the wellbore for production.
In some applications, fracturing treatments are difficult or not feasible. For example, when certain types of completions are to be placed in a wellbore, the fracturing treatments would need to be run before the installation of the completions. In other words, the fracturing treatments would need to be carried out in an open-hole configuration. This approach, however, is difficult particularly in weak formations. If a fracturing treatment is carried out, the weak formation can result in a filled or partially filled wellbore that blocks installation of the completion.
The present invention relates generally to a technique that facilitates fracturing in a variety of applications. The technique is particularly amenable to use in application where a completion, such as a sand screen or filter is to be run to a desired location within the wellbore. The technique utilizes a tubular that is placed in the wellbore at a region to undergo a fracturing treatment. The tubular has a plurality of transverse openings that permit the transfer of pressure and fluid from inside the tubular to the formation. According to one embodiment, the tubular is inserted into the wellbore in a contracted state and then expanded radially towards the wellbore wall.